1. Field of the Invention
This invention relates to linerless labels and, in particular, to pressure sensitive adhesive linerless label assemblies that can be applied to a substrate, with a portion of the assembly being subsequently removable from the substrate.
2. Description of Related Art
Linerless labels, such as shown in U.S. Pat. Nos. 5,292,713, 5,324,078, 5,354,588, and 5,578,352, the disclosures of which are incorporated by reference herein, are known to have advantages over conventional pressure sensitive labels that are mounted on a separate liner having a release coating. In conventional labels, the liner acts as a support for transport, printing and storage, and is discarded after the label is removed from the liner. In contrast, a linerless label has a face surface that is coated with a release coating and a back surface that is coated with a pressure sensitive adhesive (PSA). A strip of linerless labels may be wound in a roll configuration so that the PSA on the back side of the strip is in contact with the release coating on the face side of the strip, where the release coating faces outwardly. The adhesion between the PSA and release coating holds the strip in a roll. Labels can be peeled off individually from the roll of linerless labels, without having a liner web to tear off and discard each time a label is used.
Because a liner web is not needed in a roll of linerless labels, certain advantages and cost savings are realized, including substantial material reduction due to the lack of a liner, elimination of the disposable liner and costs associated with release coated liners, and space savings in that a roll of linerless labels can have about twice as many labels as a same size roll of labels with liners. Moreover, linerless labels have significant environmental advantages over linered labels because of the elimination of the need to dispose of the liner after each use.
Label assemblies having a removable portion of the label are known. U.S. Pat. No. 4,724,166 to deBruin discloses a linered label assembly that, after removal of the liner, can be applied to a substrate; thereafter, a portion of the assembly can be removed from the substrate, leaving the remainder of the assembly on the substrate. The deBruin assembly includes a sheet of stock material, a first dry coating layer on the stock material and a second dry coating layer on the first coating layer, a pressure sensitive adhesive coating layer on the second dry coating layer, and a coated liner backing web on the adhesive. The first and second dry coating layers are substantially incompatible so that, after removal of the liner web from the adhesive and application of the adhesive to a substrate, the first and second coating layers separate from one another, leaving the adhesive and second coating layer attached to the substrate.
Because the deBruin patent label assembly uses a liner web, it suffers from the disadvantages of linered labels generally as discussed above. In addition, the patent discloses that the first and second coatings can be any combination of polyamide varnishes, acrylic ester varnishes, and wax containing release compositions.